Fertilizer K Management Effects on Cotton Yield and Nutrition

Anthony Bland and J. J. Varco


Recent concerns over K deficiency as a limiting factor in cotton production have prompted a critical evaluation of current and alternative K fertilization practices. The overall objective of this study was to determine the effects of K rates and application methods on cotton lint yield, nutrition, and soil test K levels. This study was initiated in 1992 on an Adler silt loam soil at Greenwood, MS and a Collins silt loam at Grenada, MS. Both soils tested low in available K. Fertilizer treatments included broadcast rates of 0, 40, 80, 120, and 160 lb K/acre, 30 and 60 lb K/acre banded in combination with broadcast rates of 40, 80, and 120 lb K/acre, and 30 lb K/acre as a liquid sidedress at early square with broadcast rates of 40, 80, and 120 lb K/acre. Additional treatments at Greenwood included in-row deep placement of 150 lb K /acre with and without 30 lb K/acre as a liquid sidedress. The experimental design was a randomized complete block with four replications. Measured parameters included leaf blade and petiole K concentration at early bloom, lint yield, and soil test K levels after the first year of treatments. Leaf blade and petiole K increased with increasing rate of broadcast applied K, while banded K, either dry at planting or liquid sidedress did not result in a consistent increase above that of broadcast alone. Soil test K increased with increasing rate of broadcast applied K for the 0 to 6 in. sampled depth only. Deep placement of K resulted in soil test levels comparable to an equivalent rate of broadcast applied K. Although K nutrition was improved with K fertilization, lint yields were not significantly increased at either location for the two years of this study.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pg. 1573
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998